Apparatus and method of drying pulp articles



Jan. 1o, 1933 Filed March l5, 1929 F. D. GRAY APPARATUS AND METHOD OF DRYING PULP ARTICLES 2 Sheets-Shed l Jag. .10, 1933.

F. D. GRAY APPARATUS AND METHOD OF-DRYING PULP ARTlCLES Filed March 15x. 1929 2 Sheets-Sheei 2 ,4L T1 E -i 7 @mud-nto realized im. io, ieee essere? FREE D. GR'Y, @F NEW "'ERK; T@ Pfm@ GQRFIMLTQN, A @F MPARUS ihis application is a continuation in part of my application led July 21, A1927, Seral No. 207,361 for cartons for fragile arti'- c es. 5. The improvements relate .primarily to the means and methods for producing sheets of material, with protuberances for packing eggs or other articles, from wood pulp-or other iihrous material. The improved means l@ and methods may also loe empioyed in the production of other articles such as plates, receptacles, pulp articlesoi the cutlery type,and others. The improvements accordingly have a wider application than that herein described and illustrated, the illustrations loe-- ing merely exemplications of an embodiment of the improvements.

primary object,` among others, of the improvements is to provide a novel trayor former 'for drying articles, whereby the lat ter maybe readily removed without sticking or adlring` to the tray. Aenovel type oi die, for forming protuberances in such articles, constitutes' another object of the improvements.

A further object is to provide a method for speedily and uniformly drying'wet pulp articles o'the type suggested, as well as to provide novel means for practicing same.

A still further object is to provide means and methods for forming ribs on the articles. The tendency of wet pulp or paper articles to curl or crimp on being dried has long presented a diiiiculty in the chosen field of invention. The present improvements are accordingly designed to eliminate and prevent this undesirable feature by novel means, and methods employed in the drying stage. Other objects are to generally improve and facilitate the manufacture of pulparticles, so that production of the articles 1s speeded up and economy in. time and labor is at-- tained.

Further objects and advantages .of the present improvements will be apparent to those skilled in the art upon reference to the accompanying specification and drawings, in which- Fig. 1 is a plan view of a drying tray ilinstrating a portion of 'the present improve ments;

2 is an enlarged fr gmentary viewg 3 is a section taken on line 3-`3of 1 a `4 ig. 4 is a diagrammatic view illustrating the steps in the method; Fig. 5 is a plan view of a part of a modied form ot tray;

ti is an end view of the device of e0 is Fig. 7 is a artial'side view of the tray illustrated in ig. 45.

Referring to the drawings, Figs. 1, 2 and 3 represent one embodiment ofthe invention o5 by Way of illustration. The tray and` dies 'therein set Aforth are adapted to be employed in the course of manufacture of pulp articles such as illustrated and claimed in my aforementioned copending application.

Y The tray 10 comprises a hollow metal frame having a `base portion 11, depending side walls 12, 13 and depending end wallslfl: and 15. A hoilovv area is thus dedned immediately beneath the metallic hase 11, said area having free communication with the atmosphere. Portions of the base 11 mayV be perforated in groups, as h apertures 16 to 23, so that a pluralityy o air passages or ports are provided for communication e0 through the metallic base 11.

Associated with the interstices of said perforated portions, are. forms or dies 24 comprising upstanding ribs 25 to 32. As illustrated these ribs 'are radially disposed with S5 respect to a verticalaxis passing through knob 33. Each such rib is in the nature of a iin, since it is an imper-forate piece of metal integral with metallic base 11 and has a common connection with complementary ribs of 9@ Athe group at the aforementioned vertical axis. As seen in Figs. 1 and 2, the ribs are disposed between the interstices oi the per orated area. Upon reference to Fig. Si,

is noted that the-outer surface of the ribs converge to a common point 33 whereby a dome-shaped luted form or die 24 results. Accordingly, the form comprises a plurality of. radially disposed tins or ribs defining a plurality of 'sector-shaped spaces, the latter 100 half sections 51 apart to convenience in drafting. The tray 10 is provided with transverse guide means 34 and .35 and a longitudinal rib 36, and itis understood that each quarter of the base 11 is provided with a group of twelve perforate areas and associated forms.

Itis notable, upon reference to Fig. 1, that the base 11 has an imperforate portion 37 surrounding the groups of forms and this surface as well as the forms are circumscribed by a defiector or upstanding flange A38 (see Fig. Transverse grooves 39 are provided in base 11, and, as seen in Fig. 3,

these grooves are deeper at one end than' at the other, thereby presenting an inclined Sur ace.

The tray and the parts so far described are formed in an integral piece, with the forms 24, flange 38, rib 36, etc., upstanding on metallic base 11. The composition-of the tray is highly important and is preferably made of aluminum alloy of subs antially the following percentage composition:

Aluminum 75.75, iron 9.95, copper 13.38 with traces of zinc, silicon and lead.

It has been discovered that the best results are attained by employing-a tray of this character, as hereinafter set forth. The

f ends of the tray- 10 are provided with s up` ports `or bearings 40 whereby the tray may be suspended or otherwise supported in connection with an endless chain or carrier.

Referring to Figs of tray 50 is illustrated having forms or dies 51 thereon. As seen in, these figures, the

forms are of half-bottle configuration whereby pulp articles of lthe type described and c aimed in the application of Leon Mann filed December 14,- 1927, Serial No. 239,877

may be manufactured. This tray 50 is also 1 formed of aluminum alloy and is of the -same neral configuration as the tray 10, having the metallic base and sides, 52 to 56 respectively. .Y

yThe upstanding forms or dies 51 .comprise rovide a cavity 57 (Fig. 7 extending a ong the longitudinal axis of each die 51. A portion 58 of metallic base 52 serves to hold the sections in the illustrated position, while said base is`transversely apertured at 59 thereby providin an air passage, by means of-cavity 57, t rough tothe underslde of tray 50.v The curved surface of the die sections 51A and 51B is defined bg' ribs 60, between which cavities 61 are forme 5 to 7, another form Aand 51B suitably spaced' some of @said cavities communicatin with apertures 62 provided in base 52. Alt Vough the necks of the bottle forms are provided with ribs and spaces 61, the base 52 is imperforate therebeneath. By this arrangement, communication is afforded through the base 52. Accordingly this form also comprises a plurality of radially disposed fins or ribs 60, defining a plurality of spaces which communicate with the under portion of the base 52. -The ribs are united by a common connection 63, of the section 51A or 51B, as the case may be.

The imperforate portion 37, of Fig. 1, finds its .analogue in the tray 50 inimperforate .surface 64, and the deiector or'ffiange 38 finds its equivalent in tray 50 in the circumscribing flange 65. Tt is notable -that both elements designated 64 and 65 traverse the ends of the forms or dies 51. This is more clearly apparent upon reference to Figs. 6 and 7, and in Fig. 6, the end 66 of the'neck portion of the form is shown to incline downwardly to the base 52.

A machine for practicing/the improved methods, in conjunction with the novel trays previously described is tliagrammatically illustrated in Fig. 4. In the manufacture of pulp articles such as illustrated in my co. pending application, that of Mann, and others, `the sheets are formed by thev well known felting process with the cups, recesses or other protuberances desired in the sheet, preferably havingthe chosen outline with substantially smooth `11nbroken walls. This is accomplished by passing suitable forms on drum 70 (Fig. 4')-through a bath 71 having libres suspended therein, while suction is maintained on the inner side of the forms on drum 70, to draw the fibres a ainst them `and form a layer or sheet of f1 rous material. These sheets obviously take the contour of the form and have a base as well as protrudin domes or recesses, depending on the form. hese sheets are then transferred in a wet,

vsoft condition to the complementary transferring drum 72, whence they are transferred vto the trays 10 or 50 (as the case may be) comprising an endless carrier 73, whence the wet sheets, now on the trays, are conyeyed through the drier 74 and subsequently removed in a d state.

IFeferring more particularly to the present improvements, the heat maintained in drier 74 is lsubstantially 700 Fahrenheit, so that the trays 10 acquire and retaina high degree of heat. The trays onthe carrier 73 therefore approach the transferring drum 72 in a highly cated condition. The guides v34and 35 co-a'ct with complementary members for insuring the accurate alignment of the trays with the drum 72. Accordingly when trays 10 are-brought into juxtaposition with drum 7 2, the dies or forms 24 are in proper position for receiving `the wet pulp sheets having the cups or recesses, which latter, when transerred, will have a nice fit upon the tray l0.

When the tray and drum 7 2 come into proper alignment, pressure such as compressed air, is applied to the under side of the Wet sheet on the drum, so that said sheet is torcibly ejected or blown onto tray 10. As the forms 24 on tray 10 correspond in number, size and position to the cups of the wet sheet, the forms engage the inside surfaces of the cups. The forcible thrust of the sheet, onto the heated tray 10, causes the ribs of the forms to impress the cups of the wet sheet with corresponding protruding ribs or corrugations, while at the same time a hump. is formed at the apex of the dome by knoh 33. Such a wet sheet is shown, `after transfer, in dotted lines l0() (Fig. 3). Upon reference to this ligure, it is seen that the laterally extending portions of the sheet 100 lie against the base ll, with the circumferential part of the sheet on the surface 37 and the edges of the sheet substantially meeting the base of the deflector or flange 88. t is notable also, that said ange extends upwardly a slight distance above the four edges of the sheet. ln order that the finished sheet may have a hinge for folding the cup sections together, the rib 36 is provided as seen in Fig'.

Immediately after this transfer is e'eoted, the carrier proceeds to convey the wet sheet, while on the tray, to the drier 74. llt is to he noted that at this stage the opening of the pores of the sheet is elected. 'ilh'isis accomplished by the very hot metal tray l@ contacting the wet pulp sheet. The heat ohviously causes some steaming of the water particles in the sheet, which open the pores thereof upon egress et the steam through and from the sheet. lt is dicult to determine just when the pere epening step in the method is but it is eelieved vto continue for a short period after'the tray has entered the drier..

The het tray and wet sheet thereon new enters the drier 7d at opening 75. dust inside said opening is the discharge port 7@ of a hot air duct- 77, through which highly heated air is forced velocity hy a flan 7d or other ineens. n 7 3 describes a tertuons course threugh drier 74, leaving same at exit 'Z9'. Adjacent said port 79, an exhaust duct 8G- is dispesed.

exhaustt'an 8l ceminunicates therewith and. functions to keep the heated air entering at port 76, at a high velocity throughout the drier, until it is withdrawn at port 89.' Any other arrangement efl :duets may he eniployed in practicing the improved method. For example, additional ducts he provided for inja ing air at intermediate portions oi the y Due to the sinuous path which the on carrier 73 are compelled to take, it is apparent that the trays remain 'exposed to the heat- As illustrated, the carrierA ed air inthe drier for a predetermined period, and during this period the tray and wet sheets thereon are exposed at all times to the heated 'air at a high velocity. 'This hot air accordingly attacks the wet sheet from all angles, viz, through the perforated portions in the bottom of the tray to the underside of the sheet, downwardly upon the sheet as well as laterally at the sheet from all directions.

lt is believed that a thin film of water or steam obtains between the under surface ef the sheet and the adjacent tray surface. F requent sticking or adhesion of the sheet to the tray, after drying, yis ascribed, among other.

reasons, to this minute ilm exerting a suction. lin the present method, the heated air entering the interstices in hase l1 from heneath, attacks this ilm, drying it out, so that heated air takes its place and is free to enter the opened pores oit the sheet and dry out the pulp mass of the sheet through its veryV interior texture. `This action obviously promotes uniform application of the heated air throughout the length and breadth of the sheet. c

While the foregoing drying process takes place from beneath the traveling trays, the drying is accelerated concurrently in the following manner. The high velocity heated air which impinges the tray in a lateral direction, contacts the barrier or deflector 38, and is deected in arcs toward the central upper surface of the sheet where the deflected air impingcs the sheet and accelerates the drying of the central portion thereof. Experience has taught that this part of the sheet, regardless et the temperature maintained in the drier, has almost universally heen found to he damp upon exit from the drier. Accordingly, the method of deflecting the air to the center of the sheet, serving as an added applicationl of heat at this area- (where most needed has heen found, in actual practice, to solve the proble-rn. lliith the employment of this methcd, the sheets come out of the drier, uniformly dry.

)lt is also notable that in omitting the deector or flange 38, the sheets come out curled or crimped along their edges, therehy necessitating clipping er cutting to obtain. a straight edge. l lily pret". this dange 38, a double function thercey results, since the edges of the sheets rein and straight, so that no curling or erin i results. he yiiiished article therefore cernes outfit the drier and no shearing et the edges is required.. This novel result is ascribed to the tact 'that the wet edges ofthe sheet are pretected from the direct velocity cir' the het air .are dried te the very tipsv hy the-applicatinn or" the air in inanner described.

hvieusly the eregning steps the methed are caused te taire place throupheut the period of tra-vel in the drier appreach of the tray te exit 7 d, it is ohvions that v`the tray as well as the sheet thereon are both in a highly heated state. Accordingly a slight cooling of the sheet is accomplished in the last stage of travel between the ports 80 and 79. This is dueto the fact that the eX- haust fan 8l, sucks in cold air through port 79, whereby a cooling current passes over the emerging tray and sheet in the last portion of its travel.

As the trays, bearing the dried sheets pass out of the drier 7 4, the finished article is removed by the automatic take off 85 which is provided with one or more lingers suitably arranged to enter the grooves 39, so that said fingers are disposed beneaththe sheet and remove saine from the tray. It is understood that the endless carrier 7 3 is' made up of a plurality of trays which successively,

y pick up a Wet sheet from drum 7 2,' carry it :edges of the sheets is prevented in the same through drier 74, leave it attake oit 85, and returnto drum 7 2 for another sheet.

Where it is desired to manufacture sheets for packing bottles, the forms on drums 70 and 7 2 are provided accordingly and the carrier 7 3 is made up of trays 50 (Fig. 5). The wet pulp sheets accordingly go through the same steps of the method previously set forth and are removed by the take off device 85, wherein the lingers enter the cavities 57 (beneath the sheet and between sections 51A and 51B) and remove the dried sheets. It is notable in using this tray that ribs are Jformed on the wet pulp sheet by the ribs 60 of the form under the influence of the pressure transfer from drum 72. Likewise a longitudinal rib is formed on the central portion of the bottle shaped cup or recess due to the clearance or spacing between opposed edges 63 of sections 51A and 51B. 1

In using tray 50, crimping or curling of the fashion as previously described, since the sheets lie on the imperforate surface 64, with their edges against and protected by the upstanding barrier or detlector 65.

Attention is directed to the fact that stck- 7 ingvor adhesion of the nished sheet to the adhering diiiiculty.

Furthermore the tray of the present Aimprovements is a better conductor of heat and not only can be heated to a greater temperature but also retains such lheat better than theV alternatives mentioned above, It is notable that shrinkage of the pulp article to vbe dried, isfprevented which is an inherent result atproduced on the cups of the sheets.

tending the use of the improved tray. Uniform and more speedy drying results in the use of the aluminum alloy tray in connection with the novel stepsevolved,`so that a. larger number of sheets can be manufactured, run through the drier, removed and marketed (withoutshearing curled edges) in a given period.

The impeiforate surrounding portion of the tray in addition to cooperating with the upstanding iiange to prevent curling, also causes slower drying of the sheet at those areas than at the areas where the perforatons are located,'for example at the cup portions. I

It is apparent that any desired type of pulp article may be manufactured by utilizing the described means and methods.; For example, so called paper plates, cup, or paper cutlery articles, as well as others may be manufactured, by suitably producing a tray with 'the desired forms thereon. Likewise cushion members such as produced by knobs 33 or reinforclng ribs or corrugations may be formed on the sheet by any desired arrangement ofA the upstanding elements of the tray.

In this connection it is seen that, during the drying treatment, the heated air lmay cause the fibres to shrink a slight .amount which causes the depressed inwardly curved segments, between the ribs of the cups aswell as 4the ribs formed thereon corresponding to the rbs of the forms, to be accentuatedfthereby giving a sharper outline to the parts thus This manner of forming corrugations, etc., on the cups or recesses may be practiced independently of the pressure method but preferably attends the practice of the latter method, although not essential thereto.

The. advantages and results atta-ined by using pulp shelets .the trade, made in the manner set forth is more fully Iset forth in my copending application, wherein the functions of the -reinforcing ribs, etc. of the finished product are described.

Various modifications of the present' improvements will be apparent to those skilled in the art, and it is understood that theV improvements are notzto be lmited to the details, set forth bypway of example.

I claim:

1. A drying form comprising a foraininated base and upstanding membersv integral therewith between the interstices of said base,

2. A drying tray comprising a metallic base having foraminated portions, upstanding said members having a common connection.

members integral therewith between the in- 'terstices of said portions, members of a porsesgos of said portions, a flange protrudin upwardiy Vfrom said base and circumscri ing said portions, and a groove traversing said base.. 4. A drying tray for drying pulp articles comprising a metallic base having an imperorate circumferential surface, portions having perorations encompassed oy said surface, and upstanding forms integral with said base dening a shell over parts of said perforations, said forms defining spaced ribs istermediateadjaeent perfor-ations.

5. In the .manufacture of pulp articles wherein wet pulp fibres are united into sheet form, the method of drying such sheet and preventing crimping of the edges thereof comprising subjecting? the wet sheet to a heated form, opening the pores oi said sheet, exposing said sheet to a current of heated air and protecting the sheet edges from rect application of said current'.

6. The method of uniformly drying wet puip articles comprising placing the article. on. a head forni, subjecting same to a current of heated air, deflecting the heated air from direct Contact with the edges ci the articles and directing itagainst the interior surface of the article-and removing the article from the form.

sage extendin through said metallic base and through t e face of said form.

11. A drying tra for drying pulp articles comprisin a meta ic base having a plurality of' protru ing forms integral therewith, said forms having rounded surfaces and upstanding spaced portions, elongated openings ex-v tending between and separating the spaced portions and deiining a pluralit of ai'r passages perforations extending t rough said metaiiic base and communicating with said passages, said passages extending through the rounded surfaces of said forms.

Witness my hand this 13th day of March, 1929, county-of New York, -State of New York.

FRED D. GRAY.

7 A drying tray for'drying moist puip ari ticles comprising a metallic hase adapted to receive a one-piece article for drying, up-

standing forms integral with said hase, each form comprising a cup of spaced ribs, said hase being provi ed with a plurality of groups of apertures fory aording communil cation through the hase, the apertures of a group heingsymmetricaiiy arranged between adjacent ribs of a group, the maior portions of sai-cl ribs being disposed within the area dened by the limits of said apertures.

8. A drying tray for drying puip articles comprising a metallic base having a plurality'of spaced forms integrai therewith, one of said forms. comprising upstanding spaced portions defining the limits of the form elongated o enings extending `between and separating t e opstanding spaced portions ci the form, said base being apertured between the opstanding portions of said form.

9. A dryingtray for drying articles comprising a metallic base having an indi7 vidiiai upstanding form integral therewith, said form being made up of portions spaced from one another wherehy'opeii spaces are provided through the form, and aperture through said hase between, atleast two of said spaced portions and communicating with the open space therebetween.

10., A drying tray for puip articles comprising a metallic base having a plurality of protruding forms integra-i therewith, one

of said forms having upstandirig spaced piere-v tions, elongated opening extending he tween and separating adjoining-spaced por tions one defining an air passage, said paslizo ias 

